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Classical application problems of inequality in seventh grade
(1) Important: The price of schoolbags is twice that of cultural shirts, which is less than that of 6 yuan.

It can be converted into: 1 schoolbag price = 1 cultural shirt ×2-6 yuan.

That is:

?

=

18

×2-6

30 yuan

The price of a schoolbag is 30 yuan.

(2) Key points

The cost is not less than that of 350 yuan but not more than that of 400 yuan to reward outstanding students in mountain primary schools.

The remaining funds shall not exceed 1800-350= 1450 yuan and not be less than 1800-400= 1400 yuan.

1 schoolbag

1 T-shirt =48 yuan

(30

18=48 yuan)

Not set

The remaining funds can also buy a schoolbag and a cultural shirt for each of X primary school students.

Enumerable inequality set: 48x

≤ 1450

48x≥ 1400

The solution is 29 1/6 ≤x≤30 1/24.

Take a positive integer

∴x=29,30